Davit.



W. L. CHAPMAN.

DAVIT.

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DAVIT.

APPLICATION HLED Nov. a. mls.

Patented May 9, i916.

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|:ooooooooopo`oloo THE coLuMBlA PumuoRAPH C0.. WASHING-rml. n4 r WILLIAM L. CHAPMAN, OF NEW YORK, N. Y.

DAVIT.

Application filed November 3, 1913.

To all whom t may concern Be it known that l, `W1LLIAM L. CHA?- MAN, a citizen of the United States, and resident of the borough of Brooklyn, city and State of New York, have invented certain new and useful Improvements in Davits, of which the following is a specification accompanied by drawings.

The invention relates particularly to davit mechanisms for ships in which the davit arms are swung by mechanical means to the inboard and outboard positions.

The invention provides such a davit mechanism having a very simple and reliable construction which combines means for effectively protecting the principal parts of the operating mechanism from interference by snow and ice or by the accidental introduction of obstructing bodies and from the direct action of sea and weather, such means comprising, in its preferred embodiment, a casing and cover therefor so arranged that they afford very complete protection when the davit arm is in its inboard position, and yet in nowise interfere with the outboard movement of the davit.

The invention also provides a construction by which the rope of each davit for lowering and hoisting the boats leads from the arm into the casing to a winding-drum which is inclosed and operates within the casing and upon which the inboard end of the rope is wound and protected.

Certain other features will be described and claimed.

In the accompanying drawings, which show a preferred embodiment of the invention, Figure 1 is a side view ofone of a pair of davits in the inboard position, the outboard position being indicated in dotted lines; Fig. 2 is a side view showing the davit as seen from the outboard side; Fig. 3 is a side view of the same at right angles to Fig. 2, partly brokenaway and partly in vertical section, and showing' the davit arm swung a little way outboard from the normal inboard position; Fig. 4 is a partial sectional view on the horizontal plane 4 4 of Fig. 3; Fig. 5 is a horizontal sectional view of the casing and interior parts on the section plane 5 5 of Fig. 1.

The davit arm 10, which is preferably formed of steel plates and angle irons, as illustrated, is pivoted at its lower end on a horizontal axis substantially at the base and outboard side of the protective casing 20,

Specification of Letters Patent.

Patented May ti, 1916.

seriai No. 798,918.

which is rigidly secured to the deck 9 of the ship or other platform. The davit arm is preferably pivoted by means of a horizontal shaft 11 Xed at each end in the casing 20. lhe outboard vertical side of the casing 2G is open, as is shown in Figs. 3 and to allow movements of the rack 13. On the side of the davit arm which is toward the casing is a plate or cover 12, which closes the outboard open side of the casing when the arm is in the inboard position, as in Fig. 1, but which opens the casing with the outward movement of the arm, as will be clear from Figs. 3 and f1. The cover 12 should make a substantially sea-proof and weather-proof lit with the casing, except for a small opening necessary where the rope 30 enters at the top of the casing, as in Fig. l.

An arc-shaped toothed-rack 13, the teeth of which are on the under side so as to prevent interference by foreign bodies falling between the teeth, is secured at its outer end directly to the davit arm, as in Fig. 3, for operating the davit arm. rl`he inboard end of the rack is rigidly secured to the davit arm by a strong brace 14@ extending from it to the foot of the davit arm, as shown in Figs. 3 and 5. r1`his rack is actuated by a worm 15 and worm-wheel 16 and pinion or spur gear 17. The worm-wheel 16 is secured to and turns the shaft 18 mounted in suitable bearings within the casing 20. To the shaft 18 is Xed the pinion or spur gear 17, which meshes with the teeth on the under side of the toothed-rack 13 to actuate it. The shaft of the worm 15 is mounted in suitable bearings in the casing, one of these being a water-tight bearing or sleeve 21 on the casing, through which the shaft projects, so as to be actuated by a crank 22 outside of the casing. rllhe pitch of the thread of the worm should be such that force from the davit arm applied to the worin-wheel 1G will not turn the worm. Consequently, the davit arm can be operated by the crank 22 on the outside of the casing and it will remain fixed at any given position without requiring a brake, pawl or holding device for it. As the davit arm moves outboard, the cover 12 of the casing moves with it, opening the casing, and the rack 13 protrudes from the then open side of the casing. It will be seen that the bent angular form of the davit arm, as shown in Fig. 3, allows space for a length of rack of nearly 90 degrees of arc between the deck or base of the casing and the upright portion of the davit arm when at the inboard position, and yet, at the same time, the upper end of the davit arm at such inboard position inclines several feet farther inboard than the upright side of the casing and the pivot of the davit arm; and also, as a consequence, the upper end of the davit lifts during the first part of the outboard motion and tends to elevate the boat from its chocks or supports. y

The boat hoisting and lowering rope for each davit of the pair is preferably a wire ropel 30, and it leads through a pivoted sheave-block 31, which is pivoted, as best seen in Figs. 2 and 3, by a hinge pin 32, on an axis extending along the arm parallel with the length of rope leading therefrom down the davit arm. Thence the rope leads over one or more suitable guide sheaves 33, and then along the inboard face of the cover 12 and down to a guide sheave 34, which is mounted on the davit arm very near the axis 11 of the davit arm and within the casing when the casing is closed. Thence the rope runs to a winding-drum 35 on a shaft 36 and is Wound thereon. The windingdrum 35 is mounted within the casing 20, so that the length of rope upon it is eifectively protected from sea and weather. The pivotal mounting of the sheave-block 31, it will be seen, allows it to swing and the rope 30 to run truly over it at all positions of the boat relative to the davit arm, as is shown by the full line and the dotted line positions in Figs-1 and 2. The shaft 36 may be actuated by suitable means; for example, as illustrated, by being geared to hand cranks 37 mounted at a convenient height on the housing 38 of the gearing.

In the drawings, the casing 2O is illus trated as constructed mainly of sheet metal and angle irons in a manner to'form the principal parts of thestationary frame of the davit mechanism, and I prefer so to combine the casing and the frame of the mechanism.

In operating the davit, for example starting from the inboard position shown in full lines in Fig. 1, the davit arm is readily swung outboard by turning the crank 22, carrying out the boat as indicated in Fig. 1, and then the winding-drum 35 of each davit is turned to lower away the boat. Reversely, in taking in the boat, after it is hoisted to the position shown in dotted lines in Fig. 1 the davit arm 10 is swung inboard by operating the crank 22.

It will be seen that the actuating mechanism for swinging the davit arm is within the casing and substantially entirely inclosed when the davit is at the inboard position, with the exception of the operating crank 22. In the outboard and intermediate positions, the casing is opened by the outboard movement of rack 13 and the cover 12, the rack 13V protruding from the casing. The position of the rack and its teeth is such that a rope falling across it or a small body falling upon it will not get caught in the teeth nor interfere'with the actuating mechanism.

It will be seen that even if the davit, in its inboard position, is exposed to the severe condition of freezing spray and snow or sleet, it is so thoroughly protected, in respect to its actuating mechanism, from obstruction and interference that great reliance may safely be placed upon it to be instantly ready and operative to get out a boat in case of disaster or emergency.

I claim and desire to secure the following:

1. A davit mechanism comprising a davit arm mounted to swing to inboard and outboard positions, actuating mechanism for swinging the arm, and a protective casing for the actuating mechanism having an opening for allowing part of the mechanism to protrude in swinging the arm and a movable cover for the casing mounted to move with the swinging davit arm and which closesvthe said opening in the casing when the arm is at its inboard position.

2. A davit mechanism comprising a 'davit arm which swings on a transverse axis to inboard and outboard positions, actuating mechanism for swinging the arm, including a rack attached to the arm, and a toothed gear wheel for actuating the rack, a protective casing for the actuating mechanism in u respect to which the said davit arm. swings and which incloses kthe rack when the arm is in its inboard position, and a cover for the said casing movable with the arm and `rack and closing the casing when the arm is-in its inboard position, said actuating mechanism having an actuating shaft extending through the casing andy provided withV a worm and worm-wheel within the casing for actuating the toothed gear wheel, and means exterior to the casing for turning the actuating shaft.

3. A davit mechanism comprising a cas; ing, a davit arm pivoted to the casing, a toothed-rack attached at one end to the arm and having teeth on the under side thereof, a brace connecting the other end of the rack with the arm, a pinion engaging the rack and turning on an axis in the said casing, and a worm and worm-wheel connected to actuate the pinion, the said casing substantially inclosing and protecting the said rack when in inboard position.

4. A davit mechanism comprisingl a cas-V ing having an open and substantially vertical side allowing the protruding movement of a rack, a swinging davit arm pivoted substantially at the base of the open vertical side and provided with a rack and Ywith a cover for the casing adapted to close the open portion of said side, and mechanismV 'within said casing for actuating the said rack, the arm being of bent angular form nclined inboard above the said vertical side of the casing when in its inboard position.

5. Davit mechanism comprising a swinging davit arm, a casing adapted to be substantially closed when the davit arm is in inboard position, actuating mechanism for swinging the davit arm mounted within the said casing and a portion of which projects therefrom when the davit arm is outboard, a

rope for lowering the boat extending from said davit arm into the said casing, and a winding-drum for the said rope mounted within the casing.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses this 31st day of October, 1913.

VILLIAM L. CHAPMAN.

Witnesses:

HAROLD BINNEY, A. PSOHIERER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

